1. Field of the Invention
The present invention relates to the field of heat exchange useful for transferring heat to or from a flow able fluid. More particularly, the present invention relates to heat exchangers, and methods of manufacturing heat exchangers, where the heat exchange occurs between fluid flows physically isolated from each other. More particularly still, the invention relates to modular construction of heat exchangers.
2. Description of the Related Art
Heat exchangers are used to exchange heat between two different materials existing at different temperatures. For example, where an environment, such as a living space, is hotter than desired, air is flowed from the living space, over or through a heat exchange surface within which a cool fluid is circulated to gain heat from the flowing volume of air, thereby cooling and removing moisture from the air which is then returned to the living space. Such a heat exchanger may include, for example, a tube within which the cooled fluid flows, and fins radiating from the tube. The flowing air passes over the surfaces of the tube and fins to enable heat exchange.
Process gas flows often require the heating and or cooling thereof. Such heat exchangers may, for example, provide as simple a construct as one process conduit passing through a second conduit, and fluids passing through the conduits at different temperatures enable heat transfer from the hot fluid to the cooler fluid through the walls of the conduit(s). Additionally, shell and tube heat exchangers are available, in which conduits, through which a process fluid flows, pass through a volume through which a heat exchange medium flows, to effectuate heat exchange therebetween through the walls of the tubes.
A heat exchanger enables heat to be input into, and withdrawn from, a heat engine, such as a Stirling engine, to enable the generation of power therefrom. One style of Stirling engine operates by expanding a gas by heating on one side of the piston, while withdrawing heat from the gas at the other side of the piston, to drive the piston in a first direction. The piston may be returned using mechanical energy, such as from a crankshaft mechanism to which multiple such pistons are mechanically coupled. Gas maintained between adjacent, nearly identical pistons, such that gas is maintained between the “cold” side of one piston and the “hot” side of another. Heat exchangers must be located between each hot side volume and each cold side volume, to either provide heat to the gas or remove heat therefrom.
Traditional heat exchanger constructs require significant space and impose significant friction losses in the gas being expanded or contracted at the hot or cold sides of the pistons in comparison to the volume of the heat exchanger. In other words, the fraction or amount of heat exchange surface available in comparison to the overall volume of the heat exchanger and to the frictional losses in the gas passing through the heat exchangers is relatively low. Additionally, if readily available heat exchangers are used, the integration of them into the Stirling engine can require other changes to the integrated device, with attendant changes to the remaining design which can result in bulkier or larger heat engine constructs, suboptimal design in other areas of the system to accommodate the heat exchanger, non-optimal frictional and energy losses in the heat exchanger, or other undesirable results.
Therefore, there exists a need in the art for a compact, configurable, heat exchanger which may be used to exchange heat between a flow conduit and an external heat supply or heat sink.